In-band QoS signaling reference model for QoS-driven wireless LANs

ABSTRACT

A station, such as a point coordinator (PC) or a non-PC station, in a basic service set (BSS) in a wireless local area network (WLAN) is disclosed. The station includes a frame classification entity (FCE), a frame scheduling entity (FSE) and a QoS management entity (QME). The FCE is logically located in a logical link control (LLC) layer of the station and has a classification table containing at least one classifier entry. Each classifier entry contains a virtual stream identifier (VSID) and a frame classifier associated with a user session. The FCE receives a data frame associated with the user session, which can be one of a voice session, a video session, a data session and a multimedia session. The data frame contains in-band quality of service (QoS) signaling information for the user session. The FCE classifies the received data frame to a selected VSID contained in a classifier entry in the classification table based on a match between an in-band frame classification information contained in the received frame and the frame classifier contained in the classifier entry. The FSE is logically located in a medium access control (MAC) sublayer of the station and has a frame scheduling table containing at least one entry. Each entry in the frame scheduling table contains a VSID and a QoS parameter set associated with a user session identified by the VSID. The FSE is responsive to the classified data frame by scheduling a transmission opportunity (TO) for the classified data frame based on the at least one QoS parameter value associated with the VSID and characterizing the user session. The QME interfaces with the FCE and The FSE.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 09/616,901 filedJul. 14, 2000, now U.S. Pat. No. 6,804,222 which is incorporated byreference herein.

The present application is related to:

-   -   application Ser. No. 09/616,900 entitled An Architectural        Reference Model for QoS-Driven Wireless LANs, invented by J.-M.        Ho, and filed Jul. 14, 2000;    -   application Ser. No. 09/617,083 entitled Virtual Streams for        QoS-Driven Wireless LANs, invented by J.-M. Ho and W. Lin, and        filed Jul. 14, 2000;    -   application Ser. No. 09/616,897 entitled Admission Control for        QoS-Driven Wireless LANs, invented by W. Lin and J.-M. Ho, and        filed Jul. 14, 2000;    -   application Ser. No. 09/616,896 entitled Frame Classification        for QoS-Driven Wireless LANK, invented by J. M. Ho and W. Lin,        and filed Jul. 14, 2000;    -   application Ser. No. 09/617,493 entitled Frame Scheduling for        QoS-Driven Wireless LANs, invented by J.-M. Ho and W. Lin, and        filed Jul. 14, 2000;    -   application Ser. No. 09/617,494 entitled RSVP/SBM Based        Down-Stream Session Setup, Modification, and Teardown for        QoS-Driven Wireless LANs, invented by J.-M. Ho and W. Lin, and        filed Jul. 14, 2000;    -   application Ser. No. 09/616,878 entitled RSVP/SBM Based        Up-Stream Session Setup, Modification, and Teardown for        QoS-Driven Wireless LANs, invented by J.-M. Ho and W. Lin, and        filed Jul. 14, 2000;    -   application Ser. No. 09/617,440 entitled RSVP/SBM Based        Side-Stream Session Setup, Modification, and Teardown for        QoS-Driven Wireless LANs, invented by J.-M. Ho and W. Lin, and        filed Jul. 14, 2000;    -   application Ser. No. 09/616,885 entitled Enhanced Channel Access        Mechanisms for QoS-Driven Wireless LANs, invented by J.-M. Ho,        and filed Jul. 14, 2000;    -   application Ser. No. 09/617,439 entitled Centralized Contention        and Reservation Request for QoS-Driven Wireless LANs, invented        by J.-M. Ho and W. Lin, and filed Jul. 14, 2000;    -   application Ser. No. 09/616,884 entitled Multipoll for        QoS-Driven Wireless LANs, invented by J.-M. Ho and W. Lin, and        filed Jul. 14, 2000;    -   application Ser. No. 09/596,712, issued Jun. 8, 2004 as U.S.        Pat. No. 6,747,959 entitled Voice-Data Integrated Multiaccess By        Self-Reservation and Blocked Binary Tree Resolution, invented by        J.-M. Ho and filed Jun. 19, 2000;    -   Continuation Application No. 10/829,113 entitled Voice-Data        Integrated Multiaccess By Self-Reservation and Blocked Binary        Tree Resolution, invented by J.-M. Ho and filed Apr. 21, 2004:    -   application Ser. No. 09/597,392 entitled Voice-Data Integrated        Multiaccess By Self-Reservation and Stabilized Aloha Contention,        invented by J.-M. Ho, and filed Jun. 19, 2000, each of which is        incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the fields of communications andnetworking. More particularly, the present invention relates to anin-band QoS signaling reference model for QoS-driven wireless networks.

2. Description of the Related Art

With the advent of digital broadband networks, such as hybridfiber-coaxial networks and 3G/4G cellular networks, packetizedmultimedia services to residential and enterprise environments arebecoming not only a reality, but also a necessity. Wireless delivery of,or access to, multimedia applications, such as voice, video and data, isconsidered viable for helping accelerate this trend.

The transport of multimedia traffic over a shared network generallyrequires specific levels of quality of service (QoS) support forachieving predictable and satisfactory network service. Technically, QoSrefers to the expectation of a session or an application to receive, aswell as the ability of a network to provide, a negotiated set of servicevalues for data transmission in terms of delay/jitter bound,mean/maximum data rate, and the like. QoS is enforced and supported bysuch techniques as effective congestion control, adequate resourcereservation, proper traffic shaping, and prioritized bandwidthallocation. With some degree of QoS guarantees, shared channels furnishtime-bounded and asynchronous services that are comparable to those ofdedicated channels.

Bandwidth utilization efficiency is another important consideration inthe design of a multimedia network. High bandwidth utilizationefficiency leads to increased channel throughput and reduced accessdelay, thereby permitting the same channel bandwidth to serve moresessions/applications with given QoS levels. In the case of bandwidthshortage, maximizing bandwidth utilization efficiency minimizes thedegradation of QoS values provided to active sessions/applications.

Unfortunately, wireless local-area networks (WLANs), such as currentlyspecified by IEEE P802.11/1999, do not support QoS transport and operateon a distributed contention or simplified polling basis. Consequently,only asynchronous and low-throughput best-effort data services areprovided.

What is needed is a technique for transforming a WLAN into part of anend-to-end QoS network having enhanced channel access, thereby providingQoS support with improved bandwidth utilization.

SUMMARY OF THE INVENTION

The present invention provides an in-band QoS signaling reference modelthat can be used to extend the functionality of the architecturalreference model of the invention. The advantages of the presentinvention are provided by a station, such as a point coordinator (PC) ora non-PC station, in a basic service set (BSS) in a wireless local areanetwork (WLAN). According to the invention, the station includes a frameclassification entity (FCE), a frame scheduling entity (FSE) and a QoSmanagement entity (QME). The FCE is logically located in a logical linkcontrol (LLC) layer of the station and has a classification tablecontaining at least one classifier entry. Each classifier entry containsa virtual stream identifier (VSID) and a frame classifier associatedwith a user session. The FCE receives a data frame associated with theuser session, which can be one of a voice session, a video session, adata session and a multimedia session. The data frame contains in-bandquality of service (QoS) signaling information for the user session. TheFCE classifies the received data frame to a selected VSID contained in aclassifier entry in the classification table based on a match between anin-band frame classification information contained in the received frameand the frame classifier contained in the classifier entry. The FSE islogically located in a medium access control (MAC) sublayer of thestation and has a frame scheduling table containing at least one entry.Each entry in the frame scheduling table contains a VSID and a QoSparameter set associated with a user session identified by the VSID. TheFSE is responsive to the classified data frame by scheduling atransmission opportunity (TO) for the classified data frame based on theat least one QoS parameter value associated with the VSID andcharacterizing the user session. The QME interfaces with the FCE and TheFSE. When the FCE cannot classify the received data frame, the FCEpasses the received data frame to the QME and the QME examines the dataframe for obtaining a frame classifier and at least one QoS parametervalue characterizing a new user session.

When the station is a PC station, the QME of the PC station establishesa virtual down-stream (VDS) for transporting the traffic of the usersession from the LLC sublayer entity of the PC station to at least onepeer LLC sublayer entity in the BSS, and assigns a VSID to theestablished VDS. The QME then passes the VSID and the frame classifierassociated with the new user session to the FCE, and the FCE adds theVSID and the frame classifier to a new classifier entry in theclassification table. The QME also passes the VSID and the at least oneQoS parameter value associated with the new user session to the FSE. TheFSE adds the VSID and the at least one QoS parameter value to a newentry in the frame scheduling table. The QME causes the PC station tosend a management frame containing the VSID associated with the new usersession and indicating the management frame being for adding the new VDSto each non-PC station that is to receive the new user session in theBSS.

When the station is a non-PC station in the BSS, the QME causes thenon-PC station to send a management frame to the PC station of the BSS.In this case, the management frame contains a special VSID, a frameclassifier, at least one QoS parameter value that are associated withthe new user session, and an indication that the management frame is forsetting up the new user session. When the PC station receives themanagement frame, the information contained in the management fame ispassed to the QME of the PC station. The QME of the PC station thenestablishes one of a virtual up-stream and a virtual side-stream(VUS/VSS) for transporting the traffic of the user session from the LLCsublayer entity of the non-PC station to at least one peer LLC sublayerentity in the BSS, and assigns a VSID to the established VUS/VSS. TheQME of the PC station also passes the VSID and the at least one QoSparameter value associated with the new user session to the FSE of thePC station. In response, the FSE of the PC station adds the VSID and theat least one QoS parameter value to the new entry in the framescheduling table. The QME of the PC station causes the PC station toreturn a management frame containing the VSID, the frame classifier andthe at least one QoS parameter value that are associated with the newuser session to the non-PC station that sent a management frame to thePC station. The return management frame includes an indication foradding the new VUS/VSS. When the non-PC station receives the returnmanagement frame, the information contained in the return managementframe is passed to the local QME. The local QME of the non-PC stationpasses the VSID and the frame classifier contained in the managementframe to the local FCE, and the local FCE adds the VSID and the frameclassifier to a new classifier entry in the local classification table.The QME of the non-PC station also passes the VSID and the at least oneQoS parameter value contained in the management frame to the local FSE.In response, the local FSE adds the VSID and the at least on QoSparameter value to a new entry in the local scheduling table.

According to one aspect of the invention, the FCE includes a timer valuefor each classifier entry in the classification table, and when the FCEsuccessfully classifies the received frame to a selected VSID containedin a classifier entry of the classification table, the FCE sets thetimer value corresponding to the classifier entry to a predeterminedvalue. The timer value for the classifier entry expires when no dataframe associated with a user session using the classifier entry issuccessfully classified by the FCE. When the timer value for theclassifier entry expires, the FCE deletes the classifier entry andpasses the VSID in the classifier entry to the QME of the station, andthe QME instructs the FSE to remove the entry containing the VSID fromthe scheduling table maintained in the station. When the station is thePC station in the BSS, the QME causes the PC station to send amanagement frame containing the VSID associated with the user sessionand an indication that the management frame is for deleting the usersession to each non-PC station receiving the user session in the BSS.When the station is a non-PC station in the BSS, the QME causes thenon-PC station to send a management frame containing the VSID associatedwith the user session and an indication that the management frame is fordeleting the user session to the PC station in the BSS. When the PCstation receives the management frame, the information contained in themanagement frame is passed to the QME of the PC station. The QME of thePC station then instructs the FSE of the PC station to delete the entrycontaining the VSID contained in the management frame from thescheduling table maintained in the PC station.

BRIEF DESCRIPTION OF THE DRAWING

The present invention is illustrated by way of example and notlimitation in the accompanying figures in which like reference numeralsindicate similar elements and in which:

FIG. 1 shows an architectural reference model for QoS support in a basicservice set (BSS) over a WLAN according to the present invention;

FIG. 2 shows an in-band QoS signaling reference model for QoS supportover a WLAN according to the present invention;

FIG. 3 shows a diagram of virtual streams for QoS support over a WLANaccording to the present invention;

FIG. 4 shows a flow diagram for an admission control technique that canbe used for QoS support in a WLAN according to the present invention;

FIG. 5 depicts a process for classifying a frame that can be used in aQoS-driven WLAN according to the present invention;

FIG. 6 shows an exemplary scheduling table that can be used for framescheduling over a QoS-driven WLAN according to the present invention;

FIG. 7 shows a signal path diagram for RSVP/SBM-based down-streamsession setup, modification, and teardown over a QoS-driven WLANaccording to the present invention;

FIG. 8 shows a signal path diagram for an RSVP/SBM-based up-streamsession setup, modification, and teardown over a QoS-driven WLANaccording to the present invention;

FIG. 9 shows a signal path diagram for RSVP/SBM-based side-streamsession setup, modification and teardown over a QoS-driven WLANaccording to the present invention;

FIG. 10 shows a diagram for enhanced channel access mechanisms over aQoS-driven WLAN according to the present invention;

FIGS. 11 a-11 c respectively show exemplary arrangements of a superframe, a contention control frame and a reservation request frame thatcan be used for centralized contention and reservation request over aQoS-driven WLAN according to the present invention; and

FIGS. 12 a and 12 b respectively show exemplary arrangements for asuperframe and a multipoll that can be used over a QoS-driven WLANaccording to the present invention.

DETAILED DESCRIPTION

The present invention provides an architectural reference model thatintegrates the lower layers (link and PHY layers) of a WLAN, ascurrently specified by IEEE P802.11/1999, with the higher layers(network and higher layers) that appear in the ISO/IEC basic referencemodel of Open Systems Interconnection (OSI) (ISO/IEC 7498-1), but not inIEEE P802.11/1999. Both the IEEE P802.11/1999 and the ISO/IEC 7498-1standards are incorporated by reference herein. Additionally, thepresent invention provides end-to-end QoS mechanisms. Such integrationinstills the QoS parameter values from the higher layers into the lowerlayers, and enables the lower layers to provide QoS traffic transportand improved channel throughput.

Compared to the existing reference model, as specified in IEEEP802.11/1999, the present invention introduces an admission controlentity (ACE), a QoS management entity (QME), a frame classificationentity (FCE), and a frame scheduling entity (FSE) for a pointcoordinator/access point (PC/AP) station (STA). The present inventionalso introduces a QoS signaling entity (QSE), a QoS management entity(QME), a frame classification entity (FCE), and an optional framescheduling entity (FSE) for a non-PC/AP STA. The ACE and the QSE mayeach be part of the QME. Further, the present invention introduces aVirtual Stream (VS) Update management frame for exchange of VSmanagement information between a PC/AP STA and a non-PC/AP STA.

FIG. 1 shows an architectural reference model for QoS support in a basicservice set (BSS) over a WLAN according to the present invention. FIG. 1shows an exemplary BSS that includes a PC/AP STA and two non-PC/AP STAsx and y. While only two non-PC/AP STAs are shown in FIG. 1, it should beunderstood that any number of non-PC/AP STAs could be part of the BSSshown in FIG. 1.

The PC/AP STA shown in FIG. 1 includes an admission control entity (ACE)that is part of a QoS management entity (QME). Alternatively, the ACEcan be a separate entity that operates in conjunction with the QME. ThePC/AP STA also includes a frame classification entity (FCE) that islogically located in a logical link control (LLC) sublayer of the PC/APSTA. The QME interfaces with the FCE, which maintains a frameclassification table containing frame classifiers that are used foridentifying QoS parameter values associated with a frame. The PC/AP STAfurther includes a frame scheduling entity (FSE) logically located at amedium access control (MAC) sublayer of the PC/AP STA. The QMEinterfaces with the FSE, which maintains a frame scheduling table thatcontains scheduling information for scheduling transmission of frames.The PC/AP STA includes a conventional station management entity (SME),which is separate from the QME. The SME interfaces with a conventionalMAC sublayer management entity (MLME) and a conventional physical layermanagement entity (PLME). The MLME interfaces with the MAC sublayer,whereas the PLME interfaces with a physical layer. The physical layercomprises a conventional physical layer convergence protocol (PLCP)sublayer and a conventional physical medium dependent (PMD) sublayer.

Each non-PC/AP STA includes a local QME that interfaces with a localFCE. The local FCE is logically located at the LLC sublayer of thenon-PC/AP STA and maintains a local frame classification table. Eachnon-PC/AP STA optionally includes a local FSE (shown in a dotted border)that, when included in the non-PC/AP STA, is logically located at theMAC sublayer of the non-PC/AP STA, and maintains a local framescheduling table for the non-PC/AP STA. Each non-PC/AP STA includes aconventional station management entity (SME), which is separate from thelocal QME. The SME of the non-PC/AP STA interfaces with a conventionalMLME and a conventional PLME. The MLME interfaces with the MAC sublayer,whereas the PLME interfaces with a physical layer. The physical layercomprises a conventional physical layer convergence protocol (PLCP)sublayer and a conventional physical medium dependent (PMD) sublayer.

End-to-end QoS signaling messages of a session or an application(session/application) are generated by the QSEs of STAs in a BSS of aWLAN and/or from outside the BSS. The end-to-end QoS signaling messagesmay indicate whether a session/application is being set up, modified, ortom down. The ACE of the PC/AP STA, which may include a module forresource control and a module for policy control (not separately shownin FIG. 1), exchanges end-to-end QoS signaling messages with the QSEs inthe BSS and/or other QoS signaling counterparts outside the BSS that aretransparent to the lower layers. Based on the end-to-end QoS signalingmessages and local policy, the ACE makes an admission control decisionfor a session/application that is being set up.

When a session/application is admitted, the resource reserved for theadmission will be reflected in the ACE, whereas the QME of the PC/AP STAestablishes virtual streams (VSs) for transporting thesession/application traffic from a local LLC sublayer entity to one ormore peer LLC entities. Established VSs become active VSs and areidentified by virtual stream identifiers (VSIDs). The QME of the PC/APSTA/further extracts a frame classifier(s) from the end-to-end QoSmessages for each admitted session/application, where a frame classifieris a set of classification parameters that can be used for identifyingthe QoS parameter values associated with the frame. Exemplaryclassification parameters include IP classification parameters, LLCclassification parameters and IEEE802.1 P/Q parameters.

The QME of the PC/AP STA passes to the FCE of the PC/AP STA the VSID andthe corresponding frame classifier that are defined for the down-streamtraffic (traffic from PC/AP STA to non-PC/AP STA) of a newly admittedsession/application. The FCE adds the VSID and classifier that aredefined for the down-stream, up-stream (from non-PC/AP STA to PC/AP STA)and side-stream (from non-PC/AP STA to non-PC/AP STA) traffic to theclassification table, which is a table of all active classifiers thatare paired with or contain VSIDs arranged in a defined order. The QME ofthe PC/AP STA also passes to the FSE of the PC/AP STA the VSID and thecorresponding QoS parameter values. Logically, the FSE maintains theVSIDs and associated QoS parameter values, plus other information, suchas data size, in a scheduling table.

Further, the QME of the PC/AP STA causes the PC/AP STA to send amanagement frame, referred to as a VS Update frame, to each non-PC/APSTA participating in a newly admitted session/application. The VS Updatemanagement frame contains information, such as VSID, frame classifier,VS Action (i.e., Add VS) and QoS parameter values, that defines thedown-stream, up-stream or side-stream traffic of thesession/application. After a non-PC/AP STA receives the informationcontained in a VS Update management frame and passes the information toits local QME, the local QME relays to the local FCE of the non-PC/APSTA the VSID and classifier, and to the local FSE (if any) of thenon-PC/AP STA the VSID and QoS parameter values, for the up-stream orside-stream traffic.

An FCE, whether located within the PC/AP STA or a non-PC/AP STA,classifies frames passed down to the LLC sublayer to a VSID. The FSE ofthe PC/AP STA schedules transmission opportunities (TOs) for framesclassified to specific VSIDs based on the QoS parameter valuesassociated with the VSIDs. The FSE of a non-PC/AP STA chooses dataframes from its active VSs based on the QoS parameter values of thoseparticular VSs for transmission over the TOs scheduled by the PC/AP STA.

When the QME of the PC/AP STA detects from end-to-end QoS signalingmessages received by the ACE a change of QoS parameter values for anadmitted session/application, the ACE makes a new admission controldecision regarding the “changed” QoS parameter values. When the changecannot be accepted, the QME takes no action for the PC/AP STA and thenon-PC/AP STAs participating in the session/application. When the changeis accepted, the resource reserved for the modified QoS parameter valueswill be reflected in the ACE, and the QME updates the FSE of the PC/APSTA with the new QoS parameter values using the admitted VSIDs for thesession/application. The QME further causes the PC/AP STA to sendanother VS Update management frame to each non-PC/AP STA participatingin the modified session/application. The VS Update frame containsinformation relating to the admitted VSID, the VS Action (i.e., ModifyVS), and the new QoS parameter values. After a participating non-PC/APSTA receives a second type of VS Update frame, and the non-PC/AP STApasses the information contained therein to its local QME. The local QMEupdates the local FSE (if any) of the non-PC/AP STA with the VSID andthe modified QoS parameter values for the up-stream or side-streamtraffic of the session/application. Subsequently, the FSEs of both thePC/AP STA and the non-PC/AP STA (if any) schedule VS transmissions basedon the modified QoS parameter values.

When the QME of the PC/AP STA detects from end-to-end QoS signalingmessages received by the ACE a termination of an admittedsession/application, the resource released by the termination will bereflected in the ACE, whereas the QME identifies the particular VSIDsestablished for the session/application. The QME of the PC/AP STAinstructs the FCE of the PC/AP STA to remove from the classificationtable the VSID and the corresponding frame classifier associated withthe down-stream traffic of the session/application. The QME of the PC/APSTA also instructs the FSE of the PC/AP STA to remove from thescheduling table the VSIDs and the corresponding QoS parameter valuesassociated with the session/application. Further, the QME of the PC/APSTA causes the PC/AP STA to send another VS Update management frame toeach non-PC/AP STA participating in the session/application. The VSUpdate management frame now contains information relating to VSID and aVS Action (i.e., Delete VS) that defines the down-stream, up-stream, orside-stream traffic of the session/application. After a non-PC/AP STAreceives the information contained in the VS Update management frame andpasses the information to its local QME, the local QME instructs thelocal FCE of the non-PC/AP STA to remove from the local classificationtable the entry containing the VSID admitted for the up-stream orside-stream traffic of the session/application. The QME also instructsthe FSE (if any) of the non-PC/AP STA to remove from the localscheduling table the entry containing the VSID.

The present invention also allows a non-PC/AP STA to send a VS Updatemanagement frame to the PC/AP STA for requesting a setup, modificationor termination of a session/application, while keeping admission/policycontrol and central scheduling at the PC/AP STA. The local QME of thenon-PC/AP STA causes the transmission of such a VS Update frame, whichdoes not contain a VSID, or contains a special VSID, in the case ofsetup request. The PC/AP STA receives the VS Update management frame andpasses the information contained therein to the QME of the PC/AP STA.The ACE takes appropriate action based on the information contained inthe VS Update management frame, whereas the QME of the PC/AP STA causesthe PC/AP STA to send a VS Update management frame back to the non-PC/APSTA. When the request is granted, the return VS Update management framecontains the same information as the VS Update management frameoriginated by the PC/AP STA as if the request were initiated by thePC/AP STA itself. When the request is rejected, the return VS Updatemanagement frame contains the information that the VSID indicated in theoriginal request, in addition to a VS Action (i.e., Reject VS). Theability that a non-STA can initiate such a request is especially usefulwhen end-to-end QoS messages and session/application traffic go to orcome from a non-PC/AP STA through a portal or a bridge, but not throughthe PC/AP STA.

The present invention also provides an in-band QoS signaling referencemodel that can be incorporated into the architectural reference model ofthe present invention for enabling a WLAN to support conventionalnetwork in-band QoS signaling protocols, such as IETF Diffserv and IEEE802.1P/Q. Such in-band signaling provides QoS support through layer 3(as in IETF Diffserv) or layer 2 (as in IEEE 802.1 P/Q) taggingmechanisms. Generally, tagging does not reserve network resources inadvance, and is effected through standardized combination patterns ofcertain bits in a data packet or frame. These combination patternsidentify a reduced set of QoS parameters such as flow type and prioritylevel associated with the data traffic.

FIG. 2 shows an in-band QoS signaling reference model for QoS supportover a WLAN according to the present invention. More specifically, FIG.2 shows a STA that includes a QME, an FCE that is logically located inthe LLC sublayer of the STA and an FSE that is logically located in theMAC sublayer of the STA. The FSE may be optional in a non-PC/AP STA. TheQME interfaces with the FCE and the FSE, when present.

End-to-end QoS values expected by a new in-band QoS signaling session,together with the corresponding frame classifier, are extracted directlyfrom a data frame of the new session. In particular, when the FCE of aSTA finds a data frame—the first data frame—of a new session that cannotbe classified using the current classification table, the FCE passes theframe to the QME of the STA.

In the case of a PC/AP-STA, as applicable to down-stream traffic(traffic from a PC/AP STA to a non-PC/AP STA), the QME examines theframe for obtaining the QoS parameter values and classifiercharacterizing the new down-stream session. The QME also establishes avirtual down-stream (VDS) for transporting the session traffic from thelocal LLC sublayer entity to one or more peer LLC entities, and assignsa VSID to the newly-established VDS. The QME then passes to the FCE theVSID and the corresponding frame classifier defined for the newdown-stream session. The FCE adds the VSID and classifier to itsclassification table. The QME also passes to the FSE such VSID and thecorresponding QoS parameter values. Logically, the FSE maintains theVSD) and associated QoS parameter values, plus other information such asdata size, in an entry of its scheduling table. Further, the QME of thePC/AP STA causes the PC/AP STA to send a management frame, such as a VSUpdate management frame, to each non-PC/AP STA participating in the newsession in the BSS of the PC/AP STA. The VS Update management containsinformation, such as VSID, VS Action (i.e., Add VDS), that defines thedown-stream session.

In the case of a non-PC/AP-STA, as applicable to up-stream andside-stream traffic (traffic from a non-PC/AP STA to a PC/AP STA or anon-PC/AP STA), the QME examines the frame for obtaining the QoSparameter values and classifier characterizing the new up-stream orside-stream session. The QME of the non-PC/AP STA then causes thenon-PC/AP STA to send a management frame, such as a VS Update managementframe, to the PC/AP STA of the BSS containing the non-PC/AP STA. The VSUpdate management frame contains information, such as special VSID, VSAction (i.e., Add VUS or VSS), frame classifier, and QoS parametervalues, that defines the up-stream or side-stream session. After thePC/AP STA receives the information contained in the VS Update managementframe and passes the information to the QME of the PC/AP STA, the QMEestablishes a virtual up-stream (VUS) or a virtual side-stream (VSS) fortransporting the session traffic between LLC entities, and assigns aVSID to the established VUS or VDS. The QME then passes to the FSE ofthe PC/AP STA the VSID and the corresponding QoS parameter values.Further, the QME of the PC/AP STA causes the PC/AP STA to return amanagement frame, such as a VS Update management frame, to the non-PC/APSTA starting the new up-stream or side-stream session in the BSS. The VSUpdate management contains information, such as assigned VSID, VS Action(i.e., Add VUS or VSS), frame classifier, and QoS parameter values, thatdefines the up-stream or side-stream session. After the non-PC/AP STAreceives the information contained in the VS Update management framefrom the PC/AP STA and passes the information to the local QME of thenon-PC/AP STA, the QME relays to the local FCE of the non-PC/AP STA theVSID and classifier, and to the local FSE (if present) of the non-PC/APSTA the VSID and QoS parameter values, defined for the up-stream orside-stream session. When the VUS/VSS is a VSS, the QME of the PCstation further causes the PC station to send a management framecontaining the VSID associated with the new user session and indicatingthe management frame being for adding the new VSS to each non-PC stationthat is to receive the new user session in the BSS.

The FCE shown in FIG. 2 classifies frames passed down to the LLCsublayer to a VSID using its classification table. The FSE of the PC/APSTA schedules transmission opportunities (TOs) for frames classified tospecific VSIDs based on the QoS parameter values associated with theVSIDs. The FSE of a non-PC/AP STA chooses data frames from its activeVSs based on the QoS parameter values of those VSs for transmission overthe TOs scheduled by the PC/AP STA.

Besides the classification function, the FCE also maintains a timer foreach entry of its classification table for detecting termination of asession. When a data frame is classified successfully using a specificentry, the FCE resets the corresponding timer to a predetermined value.When the timer expires before the entry is used for classifying anotherdata frame, the FCE passes that particular entry to the QME of the sameSTA and then deletes the entry from its classification table. The QMEobtains the VSID contained in the entry, and instructs the local FCE ofthe same STA to remove the VSID together with the corresponding QoSparameter values from the scheduling table. In the case when the timeoutevent occurs at the PC/AP STA, as applicable to a down-stream session,the QME of the PC/AP STA further causes the PC/AP STA to send a VSUpdate management frame to each non-PC/AP STA participating in thesession in the BSS. The VS Update management frame contains informationsuch as VSID and VS Action (i.e., Delete VDS) that defines thedown-stream session. After an addressed non-PC/AP STA receives theinformation contained in the VS Update management frame and passes theinformation to its local QME, the local QME causes the non-PC/AP STA toremove any information related to this VDS. In the situation when thetimeout event occurs at a non-PC/AP STA, as applicable to an up-streamor side-stream session, the QME of the non-PC/AP STA further causes thenon-PC/AP STA to send a VS Update management frame to the PC/AP STA. TheVS Update management frame contains information such as VSID and VSAction (i.e., Delete VUS or VSS) that defines the up-stream orside-stream session. After the PC/AP STA receives the information in theVS Update management frame from the non-PC/AP STA and passes the to theQME of the PC/AP STA, the QME instructs the FSE of the PC/AP STA toremove from the scheduling table the entry containing the VSD. When theVSID is for a VSS, the QME of the PC station causes the PC station tosend a management frame containing the VSID associated with the usersession and indicating the management frame being for deleting the usersession to each non-PC station receiving the user session in the BSS.

The present invention also provides virtual streams (VSs) over aQoS-driven WLAN that can be set up by the QME of a PC in a BSS of a WLANfor transporting, under defined QoS constraints, the traffic of anadmitted session/application from a local LLC entity to one or more peerLLC entities in the same BSS. VSs are torn down by the QME of the PC/APSTA when the underlying session or application is terminated.

Logically, a VS is a unidirectional path between a STA sourcing the VSand one or more other STAs receiving the VS in the BSS. A VS amounts toan identifiable, ordered sequence of data frames for transport within aBSS using a specified set of QoS parameter values. A VS identifier(VSID) is assigned by the QME of a PC/AP STA for identifying the VS uponthe setup of the VS. A VSID is local to, and unique within, a given BSS.A VS is defined by a triple of VSID, VS source station address, VSdestination station address, and is characterized by a set of QoSparameter values. A VS has no predefined relationship to higher-layerconcepts, such as stream, flow, connection or session. A VS existssolely within a BSS, or more precisely, within the MAC sublayer of aWLAN. An appropriate VSID is inserted into each QoS data frame passeddown to the LLC sublayer for transmission via a FCE, which is logicallylocated in the LLC sublayer, and removed upon reception at the receiverLLC sublayer before the frame is passed up to the higher layer. EachVSID is associated by the QME of the PC/AP STA with a set of QoSparameter values for the scheduling of frame transmission by an FSElogically located in the MAC sublayer.

FIG. 3 shows a diagram of different types of virtual streams for QoSsupport over a WLAN according to the present invention. A VS can be aunitcast VS or a multicast VS. A unitcast VS is used for transportingdata frames from one STA to another STA within the same BSS, while amulticast VS is used for transporting data frames from one STA tomultiple STAs within the same BSS. A VS can further be a virtualdown-stream (VDS), a virtual up-stream (VUS), or a virtual side-stream(VSS). A VDS is used for transporting data from the PC/AP STA in a BSSto one or more non-PC/AP STAs in the same BSS. A VUS is used fortransporting data from a non-PC/AP STA in a BSS to the PC/AP STA in thesame BSS. A VSS is used for transporting data from a non-PC/AP STA in aBSS to at least another non-PC/AP STA in the same BSS.

The QoS parameter values associated with each VSID, that is, the QoSparameter values expected by the session/application traffic to beserved by the VS, may be changed in the course of thesession/application, as signaled by end-to-end QoS messages and approvedby the QME of the PC/AP STA. VSs are allocated bandwidth by the FSE ofthe PC/AP STA in terms of transmission opportunities (TOs) in accordancewith the associated QoS parameter values for transporting data framesclassified to the VSs.

A QoS parameter set may be defined by parameters, such as acknowledgmentpolicy, flow type (continuous/periodic or discontinuous/bursty),priority level, privacy information, delay bound, jitter bound, minimumdata rate, mean data rate, maximum data burst, with the latter twoparameters further relating to the token replenishment rate and bucketsize of a token bucket often used in describing or shaping incomingtraffic. A STA may support multiple VSs with different sets of QoSvalues. In response to a TO, a non-PC/AP STA may transmit data fromdifferent VSs that the non-PC/AP station sources other than the VSspecifically assigned bandwidth, as seen fit by its local FSE based onthe QoS values of the active VSs sourced by the STA.

The present invention also provides a technique for implementingadmission control over a QoS-driven WLAN that does macro bandwidthmanagement for QoS traffic transport over the MAC sublayer on asession-by-session basis. According to this aspect of the invention,admission control is performed by an ACE that is logically part of a QMEof a PC/AP STA. The QME in turn interfaces with an FCE that is logicallylocated in the LLC sublayer of the PC/AP STA and an FSE that islogically located in the MAC sublayer of the PC/AP STA.

Admission control is based on new bandwidth request and currentbandwidth availability and accounts for the MAC and PHY overheads.Bandwidth is partitioned into two spaces, one space forsessions/applications of a continuous/periodic flow type and the spacefor sessions/applications of a discontinuous/bursty flow. In general,the continuous/periodic flow type is time sensitive and requiresreal-time service, while the discontinuous/bursty flow type is timetolerant and has a relatively lower priority. The FSE of the PC/AP STAof a given BSS provides feedback for every superframe through a channelstatus service primitive to the ACE, similar to a DSBM used with theRSVP QoS protocol, providing information with respect to the currentcontention-free period (CFP), such as the useable bandwidth and the usedbandwidth, respectively, for both the continuous and discontinuous flowtypes of traffic.

When a new bandwidth request is received for a session/application of acontinuous flow type, the request will be granted only when there isadequate bandwidth still unused so that admission of the newsession/application will meet its QoS requirement and while notdegrading the performance of already admitted sessions/applications.When the unused bandwidth is not sufficient for supporting the newsession/application, but adequate bandwidth that is being used for thediscontinuous flow type can be preempted for serving the newsession/application, then the new request can also be granted with theconsequence of degrading some or all existing sessions/applications of adiscontinuous flow type. When a new bandwidth request is received for asession/application of a discontinuous flow type, the request will begranted provided that the sum of the unused bandwidth plus the usedbandwidth for a discontinuous flow type having a lower priority levelthan the priority level of the new session/application is sufficient forhonoring the new request.

In any case, bandwidth reservation may be based on the burstycharacteristics of the traffic concerned, as quantified by the tokenrate and bucket size of the token bucket mechanism, or on the mean datarates using only the taken rate of the token bucket. For example,suppose that the effective channel rate (accounting for the MAC and PHYoverheads) is C; that the time duration of each superframe, whichcomprises of a CFP and a contention period (CP) as defined by IEEEP802.11/1999, is T; that the mean data rate of a session is representedby the token rate R; and the maximum data burst of a session is given bythe bucket size B. The bandwidth requirement in terms of the channeltime per CFP for such a session will be (R*T+B)/C for traffic burstinessbased admission, and R*T/C for mean rate based admission, assumingappropriate units for C, T, R and B.

FIG. 4 shows a flow diagram 400 for an admission control technique thatcan be used for QoS support in a WLAN according to the presentinvention. At step 401, the type of traffic flow is determined inresponse to a request for bandwidth for a new session/application. If,at step 401, the traffic type is a continuous flow traffic type, flowcontinues to step 402 where it is determined whether there is sufficientunused bandwidth available for allocating to the requestingsession/application. If, at step 402, there is sufficient unusedbandwidth, flow continues to step 403 where the request is granted.

If, at step 402, there is not sufficient unused bandwidth available forallocating to the requesting session/application, flow continues to step404 where it is determined whether there is sufficient bandwidth beingused by existing discontinuous flow type sessions/applications that canbe preempted. If, at step 404, there is insufficient bandwidth that canbe preempted from existing discontinuous flow typesessions/applications, flow continues to step 405 where the request isrejected. If, at step 404, there is sufficient bandwidth that can bepreempted from discontinuous flow type sessions/applications, flowcontinues to step 406 where some or all of the existingsessions/applications of a discontinuous flow type are degraded. Flowcontinues to step 407 where the request is granted.

If, at step 401, the requesting session/application is of adiscontinuous traffic flow type, process flow continues to step 408where it is determined whether the sum of the unused bandwidth plus thebandwidth for a discontinuous flow type having a lower priority than thepriority of the requesting session/application is sufficient. If, atstep 408, there is not sufficient bandwidth for the requestingsession/application, flow continues to step 409 where the request isrejected. If, at step 408, there is sufficient bandwidth for therequesting session/application, flow continues to step 410 where therequest is granted.

The present invention also provides a technique for implementing frameclassification over a QoS-driven WLAN that enables the QoS informationto pass from higher layers (above link layer) to lower layers (LLC andMAC sublayers) once per session or per session change. According to thisaspect of the present invention, frame classification is performed by aframe classification entity (FCE) that is logically located in the LLCsublayer of a station. After a frame has been classified, framescheduling of the classified frame is performed by a frame schedulingentity (FSE) that is logically located in the MAC sublayer. Both the FCEand the FSE are interfaced to a QoS management entity (QME) thatcontains an ACE or a QoS signaling entity (QSE).

Frame classification finds appropriate virtual stream identifiers(VSIDs) to label frames passed down to the LLC sublayer by examiningframes against classifiers in a classification table. The VSIDs arelinked by the QME to specific sets of QoS parameter values for use bythe FSE to schedule the transfer of frames between LLC entities. Via aQME or a VS UPDATE management frame, VSIDs are established to correspondwith classifiers and sets of QoS parameter values for an admittedsession/application. Prior to the start of the session/application,paired VSIDs and classifiers are provided to the classification table ofthe FCE, while paired VSIDs and sets of QoS parameter values areprovided to the scheduling table of the FSE.

Classifier entries are placed in the classification table in the orderof descending search priority values. A classifier entry in theclassification table is comprised of a VSID, a search priority, andclassifier parameters. The classifier parameters may be IP classifierparameters, LLC classifier parameters, or IEEE 802.1 P/Q parameters. TheIP classifier parameters are parameters such as IP TOS Range/Mask, IPProtocol, IP Source Address/Mask, IP Destination Address/Mask, TCP/UDPSource Port Start, TCP/UDP Source Port End, TCP/UDP Destination PortStart, and TCP/UCP Destination Port End. The LLC classifier parametersare parameters such as Source MAC Address, Destination MAC Address, andEthertype/SAP. The IEEE 802.1P/Q parameters are such parameters as802.1P Priority Range and 802.1Q VLAN ID. When a frame is classifiedsuccessfully in the order of descending search priorities using one ormore of the classifier parameters contained in an entry, the VSID valuecontained in the first matched entry provides the VSID to designate theQoS parameter set for the resulting MAC service primitive used forpassing the classified frame to the MAC sublayer, or otherwise the frameis indicated as a best-effort (asynchronous) frame.

FIG. 5 depicts a process for classifying a frame that can be used in aQoS driven WLAN according to the present invention. A frame 501 that hasbeen passed down to the LLC sublayer of a station from a higher layer inthe station is received by the QME of the station. The QME examines theframe for information included in the received frame that is included inat least one of the classifier parameters in at least one of theclassifier entries in a classification table 502. The QME examines theentries in the classification table in the order of descending searchpriorities when classifying the received frame. The VSID value containedin the first matched entry is used for identifying the VS 503 and thecorresponding QoS parameter set for transporting the data frame betweenpeer LLC entities of the BSS.

The present invention also provides a technique for implementing framescheduling over a QoS-driven WLAN that does micro bandwidth managementfor QoS traffic transport over the MAC sublayer in all directions of agiven basic service set (BSS) on a superframe-by-superframe basis.According to this aspect of the invention, frame scheduling is performedby a frame scheduling entity (FSE) that is logically located in the MACsublayer of a PC/AP, which can be possibly assisted by a FSE of a non-PCstation, in the BSS. Frame scheduling is based on the classificationresults, as expressed in a virtual stream identifier (VSID) for a QoSframe or in a best-effort priority value for a non-QoS frame, of an FCEthat is logically located in the LLC sublayer of the PC/AP or a stationassociated with the PC. Frame scheduling is thus guided by the QoSparameter values associated by the QME of the PC/AP with each classifiedVSID, the QoS parameter values being null for a best-effort priorityvalue.

Frame scheduling schedules transfer during the contention-free period(CFP), between peer LLC entities, of frames passed down to the MACsublayer of all the stations, including that the LLC entity within aPC/AP, in the BSS. A virtual central queue or scheduling table is formedat the PC/AP so that a QoS queuing or scheduling algorithm can beadapted for scheduling the service (i.e., transfer) of the frames queuedin actuality or by prediction at the PC/AP or non-PC stations associatedwith the PC/AP. FIG. 6 shows an exemplary scheduling table that can beused for frame scheduling over a QoS-driven WLAN according to thepresent invention. The table includes entries for queuing the traffic ofadmitted down-stream sessions (i.e., traffic to be transmitted from thePC/AP) and the traffic of admitted up-stream and side-stream sessions(i.e., traffic to be transmitted from non-PC stations) in the BSS.

An entry for the PC/AP is always present for the transfer of the trafficfrom the PC/AP to non-PC stations associated with the PC/AP. An entryfor each non-PC station in the BSS is automatically created when thenon-PC station is associated with the PC/AP for serving the best-efforttraffic from that station. An entry is also created for each VS when theVS is set up by the QME of the PC/AP for transporting the traffic of anewly-admitted session. When a VS is torn down by the QME because thesession is terminated, the entry corresponding to the tom-down VS isremoved from the frame scheduling table. For QoS traffic, each entryincludes the VSID and QoS parameter values supporting the session, aswell as a size for the data on the corresponding VS. QoS entries in thetable may be ordered in descending priority levels associated with theVSIDs corresponding to the entries.

For a virtual down-stream (VDS) (or for the PC/AP), the size value of anentry is updated when the size on the VDS (or for the best-effortdown-stream traffic from the PC) waiting for transmission is changed.For a virtual up-stream (VUS) or a virtual side-stream (VSS) ofcontinuous/periodic flow type, as indicated in the corresponding QoSparameter set, the size value of the entry is derived from theappropriate QoS values for the VUS or VSS, such as mean data rate andmaximum data burst as defined by the token bucket mechanism. The sizevalue of an entry may be changed to reflect the real size as piggybackedby the transmitting station in a frame. For a VUS or a VSS ofdiscontinuous/bursty flow type (or for the best-effort traffic of anon-PC station), the size value of the entry is provided and updated bythe sending station through either a reservation request or apiggybacking. For traffic policing or for congestion control, themaximum data size transmitted from a VS over a certain time interval,such as a superframe time, T may be restricted by the token bucketmechanism to R*T+B, assuming appropriate units for R, T and B, where Rand B are the token rate and bucket size of the token bucket.

With a central scheduling table, the FSE of the PC/AP can scheduletransmission opportunities (TOs) in the CFP for queued traffic based onthe data size in each entry and based on other QoS parameter valuesstored in each entry, such as priority level, delay bound, and jitterbound. A TO is defined by a nominal start time and a maximum durationtime. A non-PC station may also form a local scheduling table pertainingto traffic that is to be transmitted from the station, so that the localFSE of the non-PC station can choose data from appropriate VUSs or VSSsunder it for transmission in response to a given TO. When allocating TOsfor queued traffic, the FSE of the PC/AP will also consider e allocationof centralized contention opportunities (CCOs) used in centralizedcontention by non-PC stations in the BSS for sending a reservationrequest when a new burst of frames arrives in an empty buffer at thestation. Such consideration is based on a centralized contentionalgorithm.

The present invention also provides RSVP/SBM-based down-stream sessionsetup, modification and teardown over a QoS-driven WLAN and thecorresponding service interfaces. A down-stream session is definedherein to be a data flow, supported by a particular transport-layerprotocol, originating from a user outside a given BSS of a wireless LAN,passed through a PC/AP of the BSS, and destined to one or more stationswithin the BSS. FIG. 7 shows a signal path diagram for RSVP/SBM-baseddown-stream session setup, modification, and teardown over a QoS drivenWLAN according to the present invention.

A user outside a BSS initiates a down-steam session by having its RSVPagent send out Path messages of the RSVP signaling protocol. The Pathmessages are propagated to a designated subnet bandwidth manager (DSBM)located in the PC/AP of the BSS. The DSBM in turn sends Path messages tothe subnet bandwidth manager (SBM) of each station to receive thesession inside the BSS. After the SBM of a destination station receivesthe messages, the SBM of the destination station begins resourcereservation by sending Resv messages of the RSVP signaling protocol backto the DSBM. The DSBM then performs admission control with respect tothe down-stream traffic transfer in the BSS of the down-stream session.The DSBM further sends appropriate Resv messages back to the sessionsender based on the outcome of its admission decision. Path messages andResv messages for a given session are sent periodically by the sessionsender and receiver(s), and may be changed in the course of a session.The DSBM also responds to the change by sending out appropriate Resvmessages. Path messages and Resv messages are transparent to the LLC andMAC sublayers.

In particular, when the DSBM detects new Path/Resv messages of the RSVPsignaling protocol for a down-stream session to be set up, the DSBMextracts the QoS parameter values and the classifier from the messages.The DSBM then makes an admission decision on the session based on suchfactors as policy control and resource control, with resourceavailability information being provided periodically by the FSE of thePC/AP, which is logically of the MAC sublayer. When the session fails topass the admission control, the DSBM rejects the session. When thesession is admitted, the QME of the PC/AP sets up a new virtualdown-stream (VDS) for transporting the down-stream session traffic. Thatis the QME establishes a VSID for the VDS. The QME then instructs theFCE to create an entry for the VSD and classifier defining the sessionin the classification table of the FCE. The QME also instructs the FSEto create an entry for the VSID and QoS parameter values defining thesession in the scheduling table of the FSE. Further, the QME instructsthe MAC sublayer management entity (MLME) to issue a management frame,VS Update, for transmission to each of the stations to receive thesession in the same BSS. The VS Update frame in this situation containsinformation such as VSID and VS Action (Add VDS) for the down-streamsession.

When the DSBM detects a change of an admitted downstream session fromthe Path/Resv messages of the RSVP signaling protocol for the session,the DSBM extracts the new QoS values defining the session from themessages, and decides whether to honor the modified QoS request. Whenthe modification cannot be accepted, the session remains active underthe previous QoS values. When the modification is accepted, the QME ofthe PC/AP modifies the VDS serving the session to reflect the changedQoS values associated with the VDS. That is, the QME instructs the FSEto update the scheduling table with the new QoS values for the entrycreated for the session as identified by the established VSID.

When the DSBM detects a termination of an admitted down-stream sessionfrom either the Path/Resv messages of the RSVP protocol or a timeoutindication for the session, the QME of the PC/AP tears down the VDSestablished for the session/application. That is, the QME matches theclassifier defining the session/application to the VSID for the VDS. TheQME then instructs the FCE to delete the entry for the VSID andclassifier defining the session/application from the classificationtable. The QME also instructs the FSE to delete the entry of the VSIDand QoS values defining the session/application from the schedulingtable. Further, the QME instructs the MLME to send another VS Updateframe to each station receiving the session/application in the same BSS.The VS Update contains information such as VSID and VS Action (i.e.,Delete VDS) for the session.

The present invention also provides an RSVP/SBM-based up-stream sessionsetup, modification and teardown over a QoS-driven WLAN and thecorresponding service interfaces. An up-stream session is defined hereinto be a data flow, supported by a particular transport-layer protocol,that originates from a station inside a given BSS of a wireless LAN,passed through a PC/AP of the BSS, and destined to one or more usersoutside the BSS. FIG. 8 shows a signal path diagram for anRSVP/SBM-based up-stream session setup, modification, and teardown overa QoS-driven WLAN according to the present invention.

A station inside a given BSS initiates an up-stream session by havingits SBM send out Path messages of the RSVP signaling protocol. The Pathmessages are sent to the DSBM located in the PC/AP of the BSS. The DSBMin turn sends the Path messages to the RSVP agent of each user that isto receive the session outside the BSS. After a destination RSVP agentreceives the messages, the destination RSVP agent begins resourcereservation by sending Resv messages of the RSVP signaling protocol backto the DSBM. The DSBM then performs an admission control operation withrespect to the up-stream traffic transfer in the BSS of the up-streamsession on behalf of the SBM of the session sender. The DSBM furthersends appropriate Resv messages back to the session sender based on theoutcome of the admission decision. The Resv messages sent back to thesession sender are for confirmation only, and do not require therecipient, i.e., the SBM of the sending station, to perform resourcereservation for the up-stream traffic of the station, as would be thecase with the conventional RSVP signaling protocol. Path messages andResv messages for a given session are sent periodically by the sessionsender and receiver(s), and may be changed in the course of a session.The DSBM also responds to a change by sending out appropriate Resvmessages, to which the recipient (again the SBM of the sending station)will not take any resource reservation action in response. Path messagesand Resv messages are transparent to the LLC and MAC sublayers.

In particular, when the DSBM detects new Path/Resv messages of the RSVPsignaling protocol for an up-stream session to be set up, the DSBMextracts the QoS parameter values and the classifier from the messages,and makes an admission decision on the session based on factors such aspolicy control and resource control, with resource availabilityinformation being provided periodically by the FSE that is logicallylocated in the MAC sublayer of the PC/AP. When the session fails to passthe admission control, the DSBM rejects the session. When the session isadmitted, the QME of the PC/AP sets up a new virtual up-stream (VUS) fortransporting the up-stream session traffic. That is, the QME establishesa virtual stream identifier (VSID) for the VUS. The QME then instructsthe FSE of the PC/AP to create an entry for the VSID and QoS parametervalues defining the session in the scheduling table of the FSE. Further,the QME instructs the MLME (MAC sublayer management entity) of the PC/APto issue a management frame, VS Update, for transmission to the stationinitiating the session. The VS Update frame in this case containsinformation such as VSID, frame classifier, VS Action (i.e., Add VUS),and QoS parameter values for the up-stream session. Once the addressedstation receives the VS Update frame, its local QME instructs the localFCE to create an entry for the VSID and frame classifier defining thesession in the local classification table. The local QME also instructsthe local FSE to create an entry for the VSID and QoS parameter valuesdefining the session in the local scheduling table.

When the DSBM detects a change of an admitted up-stream session from thePath/Resv messages of the RSVP signaling protocol for the session, theDSBM extracts the new QoS parameter values defining the session from themessages, and determines whether to honor the modified QoS request. Whenthe modification cannot be accepted, the session will remain activeunder the previous QoS parameter values. When the modification isaccepted, the QME of the PC/AP modifies the VUS serving the session toreflect the changed QoS parameter values associated with the VUS. Thatis, the QME of the PC/AP instructs the FSE of the PC/AP to update thescheduling table with the new QoS parameter values for the entry createdfor the session, as identified by the established VSID. The QME furtherinstructs the MLME of the PC/AP to issue another VS Update frame to thestation initiating the session. The VS Update frame in this situationcontains information such as VSID, VS Action (i.e., Modify VUS), and newQoS parameter values for the session. Once the station initiating thesession receives the VS Update frame, its local QME instructs the localFSE to update the entry of the VSD defining the session in the localscheduling table with the new QoS parameter values.

When the DSBM detects a termination of an admitted up-stream sessionfrom either the Path/Resv messages of the RSVP protocol or a timeoutindication for the session, the QME of the PC/AP tears down the VUSestablished for the session. That is, the QME of the PC/AP matches theclassifier defining the session to the VSID for the VUS. The QME of thePC/AP then instructs the FSE of the PC/AP to delete the entry of theVSID and QoS parameter values defining the session from the schedulingtable. Further, the QME instructs the MLME of the PC/AP to send anotherVS Update frame to the station initiating the session. This particularVS Update contains information such as VSID and VS Action (i.e., DeleteVUS) for the session. Once the station initiating the session receivesthe VS Update frame, its local QME instructs the local FCE to delete theentry of the VSID and classifier defining the session from the localclassification table. The QME also instructs the local FSE to delete theentry of the VSID and QoS parameter values defining the session from thelocal scheduling table.

The present invention also provides RSVP/SBM-based side-stream sessionsetup, modification and teardown over a QoS-driven WLAN and thecorresponding service interfaces. A side-stream session is definedherein to be a data flow, supported by a particular transport-layerprotocol, that originates from a station inside a given BSS of awireless LAN and destined directly to one or more stations within theBSS. The data flow may also be destined to any user outside the BSSthrough a PC/AP of the BSS. FIG. 9 shows a signal path diagram forRSVP/SBM-based side-stream session setup, modification, and teardownover a QoS-driven WLAN according to the present invention.

A station inside a given BSS initiates a side-stream session by havingits SBM send out Path messages of the RSVP signaling protocol. The Pathmessages are sent to the DSBM located in the PC/AP of the BSS. The DSBMin turn sends Path messages to the RSVP agent of each user intended toreceive the session outside the BSS, and to the SBM of each stationintended to receive the session inside the BSS. After a destination RSVPagent receives the messages, the destination RSVP agent begins resourcereservation by sending Resv messages of the RSVP signaling protocol backto the DSBM of the PC/AP. The SBM of each destination station within theBSS also begins resource reservation by sending its own Resv messagesback to the DSBM of the PC/AP. The DSBM of the PC/AP then performs anadmission control operation with respect to the side-stream traffictransfer in the BSS of the side-stream session on behalf of the SBM ofthe session sender. The DSBM further sends appropriate Resv messagesback to the session sender based on the outcome of the admissiondecision. The Resv messages are for confirmation only, and do notrequire the recipient, i.e., the SBM of the sending station, to performresource reservation for the side-stream traffic of the station, aswould be the case with the conventional RSVP signaling protocol. Pathmessages and Resv messages for a given session are sent periodically bythe session sender and receiver(s), and may be changed in the course ofa session. The DSBM of the PC/AP also responds to the change by sendingout appropriate Resv messages, to which the recipient (again, the SBM ofthe sending station) will not take any resource reservation action inresponse. Path messages and Resv messages are transparent to the LLC andMAC sublayers.

In particular, when the DSBM detects new Path/Resv messages of the RSVPsignaling protocol for a side-stream session to be set up, the DSBMextracts the QoS parameter values and the classifier from the messages,and makes an admission decision on the session based on factors such aspolicy control and resource control, with resource availabilityinformation being provided periodically by the FSE of the MAC sublayerin the PC/AP. When the session fails to pass the admission control, theDSBM rejects the session. When the session is admitted, the QME of thePC/AP sets up a new virtual side-stream (VSS) for transporting theside-stream session traffic. That is, the QME of the PC/AP establishes avirtual stream identifier (VSID) for the VSS. The QME then instructs theFSE of the PC/AP, which is logically part of the MAC sublayer, to createan entry for the VSID and QoS parameter values defining the session inthe scheduling table of the FSE. Further, the QME instructs the MLME ofthe PC/AP to issue a management frame, VS Update, for transmission tothe station initiating the session. The VS Update frame in thissituation contains information such as VSID, frame classifier, VS Action(i.e., Add VSS), and QoS parameter values for the side-stream session.Once the station initiating the session receives the frame, its localQME instructs the local FCE to create an entry for the VSID and frameclassifier defining the session in the local classification table. Thelocal QME also instructs the local FSE to create an entry for the VSIDand QoS parameter values defining the session in the local schedulingtable. Additionally, the QME of the PC/AP instructs the MLME of thePC/AP to issue a management frame, VS Update, for transmission to eachstation intended to receive the session in the same BSS. The VS Updateframe in this situation contains information such as VSID and VS Action(i.e., Add VSS) for the side-stream session.

When the DSBM detects a change of an admitted side-stream session fromthe Path/Resv messages of the RSVP signaling protocol for the session,the DSBM extracts the new QoS parameter values defining the session fromthe messages, and determines whether to honor the modified QoS request.When the modification cannot be accepted, the session will remain activeunder the previous QoS parameter values. When the modification isaccepted, the QME of the PC/AP modifies the VSS serving the session toreflect the changed QoS parameter values associated with the VSS. Thatis, the QME of the PC/AP instructs the FSE of the PC/AP to update thescheduling table with the new QoS values for the entry created for thesession, as identified by the established VSID. The QME of the PC/APfurther instructs the MLME of the PC/AP to issue another VS Update frameto the station initiating the session. The VS Update frame in thissituation contains information such as VSID, VS Action (i.e., ModifyVSS), and new QoS parameter values for the session. Once the addressedstation receives the frame, its local QME instructs the local FSE toupdate the entry of the VSID defining the session in the localscheduling table with the new QoS parameter values.

When the DSBM detects a termination of an admitted side-stream sessionfrom either the Path/Resv messages of the RSVP protocol or a timeoutindication for the session, the QME of the PC/AP tears down the VSSestablished for the session. That is, the QME of the PC/AP matches theclassifier defining the session to the VSID for the VSS. The QME of thePC/AP then instructs the FSE of the PC/AP to delete the entry of theVSID and QoS parameter values defining the session from the schedulingtable. Further, the QME instructs the MLME of the PC/AP to send anotherVS Update frame to the station initiating the session. In thissituation, the VS Update frame contains information such as VSID and VSAction (i.e., Delete VSS) for the session. Once the addressed stationreceives the VS Update frame, its local QME instructs the local FCE todelete the entry of the VSID and classifier defining the session fromthe local classification table. The local QME also instructs the localFSE to delete the entry of the VSID and QoS parameter values definingthe session from the local scheduling table. Additionally, the QME ofthe PC/AP instructs the MLME of the PC/AP to send another VS Updateframe to each station receiving the session in the same BSS. The VSUpdate frame contains information such as VSID and VS Action (i.e.,Delete VSS) for the session.

The present invention also provides enhanced channel access mechanismsover a QoS-driven WLAN that greatly improve QoS capability and channelutilization on a wireless LAN over simple polling and distributedcontention schemes as defined by IEEE P802.11/1999. Channel accessaccording to the present invention is driven by QoS parameter valuesthat are associated with admitted sessions/applications. Specifically,down-stream traffic (from a PC/AP STA to at least one non-PC/AP STA) isgiven TOs directly by the FSE of the PC/AP STA in a given BSS of a WLANbased on the corresponding set of QoS parameter values, such as delaybound and mean data rate for the down-stream traffic. Up-stream andside-stream traffic (from a non-PC/AP STA to the PC/AP STA or anon-PC/AP STA) of a continuous/periodic flow type is allocated TOsperiodically by the FSE of the PC/AP STA also in accordance with thecorresponding set of QoS parameter values for the up-stream andside-stream traffic. Up-stream and side-stream traffic of adiscontinuous/bursty flow type is allocated TOs only when there is databuffered at non-PC/AP stations for transmission, with the allocationfurther being subject to the QoS parameter values. Consequently, channelbandwidth is not idled away due to inactive stations, as would be thecase when all the stations associated with the PC/AP STA were polled fordata transmission, regardless of the respective flow type of theirtraffic. QoS based channel access according to the present inventionalso allows higher priority traffic to be transferred, an importantmechanism, especially in the case of inadequate bandwidth.

The channel access mechanisms of the present invention include acentralized contention and reservation request scheme that is carriedout under the control of a point coordination function (PCF) containedin the PC/AP STA, in addition to a conventional distributed contentionscheme that is under the control of a conventional distributedcoordination function (DCF) contained equally in every STA, as describedin IEEE P802.11/1999. The channel access mechanisms of the presentinvention further include a multipoll scheme that announces multiple TOsin a single frame under the PCF, in contrast to the simple poll schemethat announces one TO in one frame, as provided by IEEE P802.11/1999.

According to this aspect of the invention, non-PC/AP stations usecentralized contention for sending a reservation request (RR) to the PCfor channel bandwidth allocation when a non-PC/AP stations have a newburst of data frames to transmit (to the PC/AP STA or/and otherstations). In each “contention-free period” (CFP) under the PCF, zero,one or multiple centralized contention intervals (CCIs) may be selectedby the PC for centralized contention. The length of each CCI isexpressed in units of centralized contention opportunities (CCOs), andis also determined by the PC. The number of available CCIs and thelength of each CCI are announced by the PC/AP STA in a contentioncontrol (CC) fame. A station, if permitted to send an RR, sends an RRinto any one of the available CCOs following a CC frame. Stations thatsuccessfully sent an RR frame in a given CCI will be identified in thenext CC frame sent by the PC/AP STA. Such positive indication may alsobe effected in the form of a TO given to the transmission of the databurst for which an RR was sent. Stations that did not successfully sendan RR frame in a given CCI may retry in the next CCI.

The phrase “contention-free period” loosely corresponds to aconventional “contention period” (CP), as defined in IEEE P802.11/1999.In contrast to the present invention, CP refers to distributedcontention as operating under the DCF of IEEE P802.11/1999, whereas CFPof the present invention implies no such contention, but can havecentralized contention under the PCF. Centralized contention enables aPC, or an FSE inside the PC/AP STA, to have complete control of channelbandwidth such that the period seized by non-PC/AP STAs for contentionis determined by the PC in advance, as opposed to distributed contentionby which STAs can seize the channel for an unpredictable duration andthereby may lock up channel access for other contendingsessions/applications. The centralized contention of the presentinvention also allows the PC to optimize the bandwidth allocation forsuch contention so that channel throughput is increased while accessdelay is reduced, compared to distributed contention. This is becausethe PC can maintain a global history of the contention outcome of allthe stations, and thus can optimally estimate the bandwidth need forcentralized contention and conflict resolution for previous contention,whereas a station using distributed contention contends based on thelocal knowledge of its own contention history and thus cannot optimizethe overall contention algorithm. Moreover, with centralized contention,stations send only RRs of very short length and only once for a newburst, while with distributed contention stations send data frames ofmuch larger length and may have to contend several times for each databurst because a data burst generally needs to be decomposed into anumber of data frames that do not exceed a predefined size. Therefore,the present invention yields much less contention intensity and, hence,much higher channel throughput and lower access delay, than aconventional distributed contention technique.

A multipoll is sent by the PC/AP STA for conveying a sequence of TOs toone or more non-PC/AP stations for up-stream and/or side-streamtransmission. A multipoll also specifies the length of each TO. Thistechnique of the present invention is particularly useful when directstation-to-station communication is involved, thereby avoiding thesituation that data frames need to be sent to the PC/AP STA first andthen back to the destination non-PC/AP STA(s).

FIG. 10 is a diagram showing enhanced channel access mechanisms over aQoS-driven WLAN according to the present invention. FIG. 10 shows asuperframe having a contention free period (CFP), a conventionalcontention period (CP) and exemplary frames illustrating the enhancedchannel access mechanisms of the present invention. A superframe isdemarcated by a target beacon transmission time (TBTT). Subsequent tothe TBTT, a PC/AP STA transmits a beacon frame, as defined by IEEEP802.11/1999. A short inter-frame space (SIFS) occurs after thetransmission of each frame in the CFP, also as defined by IEEEP802.11/1999.

Next in FIG. 10, a down-stream frame D2 is sent from a PC/AP STA to anon-PC/AP STA. The down-stream frame includes a poll for the destinationnon-PC/AP STA for sending upstream traffic to the PC/AP STA. The pollednon-PC/AP STA responds with an up-stream frame U2 that contains user ormanagement data and an acknowledgement to the poll.

An exemplary multipoll frame is shown next that conveys a sequence ofTOs for non-PC STA(s) to send traffic. In this case, there is a sequenceof four TOs that are identified by the multipoll. The first TO has beenallocated to VS13 or a different VS sourced by a non-PC/AP STA and isused for sending data frames classified to VS13. The second TO has beenallocated to VS31 or a different VS sourced by a non-PC/AP STA and isused for sending data frames classified to VS31. The third TO has beenallocated to a non-PC/AP STA and is used by the non-PC/AP STA to send adelayed acknowledgement (Dly-Ack) that acknowledges receipt of framesidentified in the Dly-Ack frame by the non-PC/AP STA at some previoustime. The fourth TO has been allocated to VS28 or a different VS sourcedby a non-PC/AP STA and is used for sending data frames classified toVS28. Traffic is sent into each respective TO. Subsequent to the TOs,the PC/AP STA sends an acknowledgement frame with a poll. Theacknowledgement frame acknowledges correct reception of a frame sentimmediately before the acknowledgement frame by a non-PC/AP STA (i.e.,the frame from VS28 according to the illustration in FIG. 10), and thepoll polls a destination non-PC/AP STA for sending upstream orsidestream traffic. The polled non-PC/AP STA, STA 4, responds by sendinga data frame to STA 5 (S45).

The CFP then includes a CC frame identifying three CCOs that can be usedby non-PC STAs having new bursts of traffic of a discontinuous/burstyflow type or of a best effort/asynchronous nature to transmit forsending an RR. The CC frame also includes information relating to theidentification of non-PC/AP STAs that successfully sent an RR in apreceding CCI to the PC/AP STA so that these non-PC STAs can determinewhether an RR needs to be re-sent in the next CCI. An RR is sent forhaving bandwidth allocated for transmitting the burst of traffic, asdefined above, that arrives at a non-PC/AP STA for transmission. In theexemplary arrangement of FIG. 10, a single RR is sent into the firstCCO, no RR is sent into the second CCO, and two colliding RRs are sentinto the third CCO. Following the CCOs, the PC/AP STA sends adown-stream frame D1 with a poll, and the polled non-PC/AP STA respondswith an up-stream frame U1 in which an acknowledgement is included.

In the exemplary arrangement of the superframe shown in FIG. 10, asecond CC frame is sent from the PC/AP STA indicating available CCOs andacknowledging receipt of a frame immediately prior to the transmissionof the CC frame. As shown in FIG. 10, a RR is sent into the firstavailable CCO whereas another RR is sent into the second available CCO.In the illustration of FIG. 10, these two RRs collided in the third CCOof the preceding CCI, but they are now sent without collision and eachreceived correctly by the PC/AP STA, thereby successfully resolving acollision. Lastly, a contention free (CF) end frame is sent indicatingthe end of the CFP and the beginning of the conventional CP in thecurrent superframe.

The present invention also provides a technique for implementingcentralized contention and reservation request over a QoS-driven WLANthat enables stations of a given BSS to report to a PC/AP of the BSS inan efficient way arrivals of new QoS or best-effort traffic burstsawaiting transmission. The FSE of the PC/AP can then place suchinformation in its scheduling table for allocating transmissionopportunities (TOs) for sending the data bursts.

Centralized contention is controlled by the PC/AP, and occurs in the“contention-free period” (CFP) of a superframe, as shown in FIG. 11 a,in contrast to a conventional contention-period (CP) that is used forconventional distributed contention. According to the invention,centralized contention, occurs in well defined centralized contentionintervals (CCIs). Each CCI is always preceded by a contention control(CC) frame that is broadcast by the PC/AP (or by a CC frame containingan acknowledgment to the last data frame received by the PC). Each CCIcontains a number of centralized contention opportunities (CCOs) forsending reservation request (RR) frames. Subject to certain centralizedcontention rules, stations send their respective RR frames using CCOs.There may be zero, one, or more CCIs in a given CFP, with the number ofCCOs in each CCI selected, as seen fit by the FSE in consultation withthe scheduling table maintained by the FSE of the PC/AP and thecentralized contention algorithm in use. A centralized contentionalgorithm determines the desired length of the following CCI in units ofCCOs, based on the contention outcome (i.e., the number of idle,successful, and colliding CCOs) in the preceding CCI and on the estimateof the number of stations generating a new RR frame since the last CCI.

A CC frame, such as shown in FIG. 11 b, contains information, such as apriority limit, a CCI length, a permission probability (PP), andfeedback entries. The priority limit specifies the minimum prioritylevel of a virtual up-stream or a virtual side-stream having a new databurst for transmission that has a privilege to trigger its sourcingstation to send an RR frame on its behalf in the following CCI. A CCIlength is expressed in terms of the CCOs contained in the CCI. A PP isused for reducing contention when the available CCI length is shorterthan the optimum CCI length, and is calculated in such cases by dividingthe available CCI length by the optimum CCI length. Otherwise, the PP isset to unity. Stations having an obligation and a privilege to send anRR frame first check against the PP to test whether they are permittedto contend for sending an RR frame. These particular stationsindependently generate a number from a random variable uniformlydistributed over the interval (0,1). When a station generates a numbersmaller than the PP, the station is permitted to contend, and nototherwise. Permitted stations independently and in a random fashionselect one of the available CCOs and send their RR frames using theirselected CCOs. The feedback entries contain the VSIDs or AIDs for whichan RR frame was correctly received by the PC/AP during the last CCI.Stations that find no such positive feedback during the CC frame willretry to send an RR frame during the next CCI under the centralizedcontention rules applied to that the next CCI, unless a station isoffered prior to the start of the next CCI a transmission opportunity(TO) for the virtual stream (VS), resulting in the sending of the RRframe.

An RR frame, such as shown in FIG. 11 c, primarily contains information,such as a data size of the VS for which the RR frame is being sent, anda VSID identifying the VS, or a data size of the best-effort traffic andthe AID of the sending station. A station generates an RR frame when anew burst of data is classified to one of its sourced VSs fortransmission. A station may also send an RR frame using a TO allocatedto the station. RR frames are generally much shorter than data frames,and hence considerably reduce contention and improve channel performancein comparison with cases where all data frames are sent by contention asunder the conventional distributed contention function (DCF) of IEEEP802.11/1999.

The present invention provides a technique for implementing multipollover a QoS-driven WLAN that allows for transmissions from a sequence ofvirtual up-streams (VUSs) and virtual side-streams (VSSs) at one or morestations by a single poll. According to the invention, such a multipollscheme extends the conventional simple poll scheme that allows fortransmission from only one station per poll, as defined by IEEEP802.11/1999, thus greatly improving bandwidth utilization efficiency ofwireless medium. The approach of the present invention is particularlyuseful when direct station-to-station communication is involved becausedata frames need not to be sent to a PC/AP first and then back to thedestination station(s).

A multipoll is sent by a PC/AP during the CFP of a superframe when it isdesirable to allocate a sequence of transmission opportunities (TOs) tovarious stations for sequential up-stream and/or side-stream datatransmissions. A multipoll frame is primarily formed based on pollrecords arranged in the order of their occurrence, with each poll recordfurther comprised of a VSID (or AID, association ID) and a durationtime. The VSID identifies a VUS/VSS sourced by the station that isreceiving a TO from a particular poll record, or the AID of the stationin situations when the TO is for a station sourcing no active VUSs/VSSs.The duration time of a TO specifies the maximum length of the TO. Thefirst TO starts a SIFS period after the multipoll frame ends, and eachsuccessive TO starts when the preceding TO limit expires. Alternatively,a TO starts a SIFS period after the station using the preceding TO sendsa data frame that is indicated to be the final frame from that stationfor its poll record, when the station using the second-in-time TOdetects such an indication. That is, when a station does not detect thetransmission termination, as indicated by the preceding station, thestation starts its transmission within TO allocated to the station. Whena station detects such a termination before the preceding TO is fullyutilized, the station may start early, but cannot use the leftoverduration time in addition to the full duration of TO allocated to thestation. In such a situation, the PC/AP does not take any action toreclaim the unused channel time. When some stations do not completelyuse their TOs allocated in a multipoll, the last station may end itstransmission prior to the nominal expiry time, and the unused channeltime is then returned to the PC/AP for reallocation.

A station, in response to a poll record containing a VSID, may transmitdata from the indicated VUS/VSS or, alternatively, from a different one,as determined by its local FSE based on the QoS parameter values of theactive VUSs/VSSs sourced by the station. When a poll record contains anAID, the station having the AID transmits data completely based on thedecision of its local FSE, again, in accordance with the QoS parametervalues of the active VUSs/VSSs.

FIG. 12 a shows an exemplary arrangement of a superframe having acontention free period (CFP), a conventional contention period (CP) andan exemplary arrangement of frames. The superframe of FIG. 12 a isdemarcated by a target beacon transmission time (TBTT). Subsequent tothe TBTT, a PC/AP STA transmits a beacon frame, as defined by IEEEP802.11/1999. A short inter-frame space (SIFS) occurs after thetransmission of each frame in the CFP, also as defined by IEEEP802.11/1999.

Next in FIG. 12 a, a down-stream frame D2 is sent from a PC/AP STA to anon-PC/AP STA. The down-stream frame includes a poll for the destinationnon-PC/AP STA for sending upstream to the PC/AP STA. The pollednon-PC/AP STA responds with an up-stream frame U2 that contains user ormanagement data and an acknowledgement to the poll.

An exemplary multipoll frame is shown next that conveys a sequence ofTOs for non-PC STA(s) to send traffic. In this case, there is a sequenceof five TOs that are identified by the multipoll. The first TO has beenallocated to VS13 or a different VS sourced by a non-PC/AP STA and isused for sending data frames classified to VS13. The second TO has beenallocated to VS31 or a different VS sourced by a non-PC/AP STA and isused for sending data frames classified to VS31. The third TO has beenallocated to a non-PC/AP STA and is used by the non-PC/AP STA to send adelayed acknowledgement (Dly-Ack) that acknowledges receipt of framesidentified in the Dly-Ack frame by the non-PC/AP STA at some previoustime. The fourth TO has been allocated to VS28 or a different VS sourcedby a non-PC/AP STA and is used for sending data frames classified toVS28. The fifth TO has been allocated to VS4 or a different VS sourcedby a non-PC/AP STA and is used for sending data frames classified toVS4. Traffic is sent into each respective TO. Subsequent to the TOs, thePC/AP STA sends an acknowledgement frame with a poll. Theacknowledgement frame acknowledges correct reception of a frame sentimmediately before the acknowledgement frame by a non-PC/AP STA (i.e.,the frame from STA 4 according to the illustration in FIG. 12 a), andthe poll polls a destination non-PC/AP STA for sending up-stream orside-stream traffic. The polled non-PC/AP STA, STA 4, responds bysending a data frame to STA 5 (S45). Lastly, a contention free (CF) endframe is sent indicating the end of the CFP and the beginning of theconventional CP in the current superframe.

While the present invention has been described in connection with theillustrated embodiments, it will be appreciated and understood thatmodifications may be made without departing from the true spirit andscope of the invention.

1. A network including a basic service set (BSS), the networkcomprising: a) a point coordinator (PC) station constituting a portionof the BSS, the PC station including: 1) a frame classification entity(FCE) logically located in a logical link control (LLC) layer of thestation and having a classification table containing at least oneclassifier entry, each classifier entry containing a virtual streamidentifier (VSID) and a frame classifier associated with a user session,the FCE receiving a data frame associated with the user session, thedata frame containing in-band quality of service (QoS) signalinginformation for the user session, the FCE classifying the received dataframe to a selected VSID contained in a classifier entry in theclassification table based on a match between an in-band frameclassification information contained in the received frame and the frameclassifier contained in the classifier entry; 2) a frame schedulingentity (FSE) logically located in a medium access control (MAC) sublayerof the station and having a frame scheduling table containing at leastone entry, each entry containing a VSID and a QoS parameter setassociated with a user session identified by the VSID, the FSE,responsive to the classified data frame, scheduling a transmissionopportunity (TO) for the classified data frame based on the at least oneQoS parameter value associated with the VSID and characterizing the usersession; and 3) a QoS management entity (QME) that interfaces with theFCE and the FSE; and b) a non-point coordinator (non-PC) stationconstituting a portion of the BSS, the non-PC station including: 1) anFCE; and 2) a QME.
 2. The network of claim 1, wherein: the non-PCstation further includes an FSE.
 3. The network of claim 1, wherein thenetwork is a wireless network.
 4. The network of claim 1, wherein theuser session is one of: a voice session, a video session, a datasession, and a multimedia session.
 5. The network of claim 1, wherein,when the FCE cannot classify the received data frame: the FCE passes thereceived data frame to the QME, and the QME examines the data frame forobtaining a frame classifier and at least one QoS parameter valuecharacterizing a new user session.
 6. The network of claim 1, wherein:the FCE includes a timer value for each classifier entry in theclassification table; and when the FCE successfully classifies thereceived frame to a selected VSID contained in a classifier entry of theclassification table, the FCE sets the timer value corresponding to theclassifier entry to a predetermined value, the timer value expiring whenno data frame associated with a user session using the classifier entryis successfully classified by the FCE.
 7. The network of claim 1,wherein: at least one classifier entry in the classification tableincludes a time value representing a maximum allowable predeterminedtime interval between consecutively received data frames; and when themaximum allowable predetermined time interval is exceeded betweenconsecutively received data frame, the user session is terminated. 8.The network of claim 1, wherein the wireless network is a wireless localarea network (WLAN).
 9. The network of claim 5, wherein, when the FCEthat cannot classify the received data frame is in the point coordinator(PC) station: the QME in the PC station establishes a virtualdown-stream (VDS) for transporting the traffic of the user session fromthe LLC sublayer entity of the PC station to at least one peer LLCsublayer entity in the BSS, and assigns a VSJD to the established VDS.10. The network of claim 5, wherein, when the FCE that cannot classifythe received data frame is in a non-PC station: a) the QME in the non-PCstation causes the non-PC station to send a management frame to the PCstation, the management frame containing: 1) a special VSID, 2) a frameclassifier, and 3) at least one QoS parameter value that is associatedwith the new user session; and b) the QME in the non-PC stationindicates that the management frame is for setting up the new usersession.
 11. A method using in-band quality of service (QoS) signalingfor a user session within a basic service set (BSS) in a network, themethod comprising: a) in a point coordinator (PC) station in the BSS,performing steps of: 1) forming a classification table that is logicallylocated in a logical link control (LLC) sublayer of a station in theBSS, the classification table containing at least one classifier entry,each classifier entry containing a virtual stream identifier (VSJD) anda frame classifier associated with a user session; 2) receiving a dataframe associated with the user session, the data frame containingin-band quality of service (QoS) signaling information for the usersession; 3) classifying the received data frame to a selected VScontained in a classifier entry in the classification table based on amatch between an in-band QoS classification information contained in thereceived frame and the frame classifier contained in the classifierentry; 4) forming a frame scheduling table logically located in a mediumaccess control (MAC) sublayer of the station, the frame scheduling tablecontaining at least one entry, each entry containing a VSID and at leastone corresponding QoS parameter value associated with a user session;and 5) scheduling a transmission opportunity (TO) for the classifieddata frame based on the at least one QoS parameter value associated theVSID and characterizing the user session; and b) in a non-PC station inthe BSS, performing: the classification table forming step; the dataframe receiving step; and the data frame classifying step.
 12. Themethod of claim 11, further comprising, in the non-PC station in theBSS, performing: the frame scheduling table forming step; and the TOscheduling step.
 13. The method of claim 11, wherein the network is awireless network.
 14. The network of claim 11, wherein the user sessionis one of: a voice session, a video session, a data session, and amultimedia session.
 15. The method of claim 11, wherein when thereceived data frame cannot be classified, the method further comprises:examining the data frame for obtaining a frame classifier and at leastone QoS parameter value characterizing a new user session.
 16. Themethod of claim 11, wherein: each classifier entry in the classificationtable includes a timer value; and the method further comprises settingthe timer value corresponding to the classifier entry to a predeterminedvalue when the received frame is successfully classified to a selectedVSID contained in a classifier entry of the classification table; andthe timer value for the classifier entry expires when no data frameassociated with a user session using the classifier entry issuccessfully classified.
 17. The method of claim 11, wherein: at leastone classifier entry in the classification table includes a time valuerepresenting a maximum allowable predetermined time interval betweenconsecutively received data frames; and when the maximum allowablepredetermined time interval is exceeded between consecutively receiveddata frame, the method further comprises terminating the user session.18. The network of claim 13, wherein the wireless network is a wirelesslocal area network (WLAN).
 19. The method of claim 15, wherein, when themethod is performed in a station that is a point coordinator (PC)station, the method further comprises: establishing a virtualdown-stream (VDS) for transporting the traffic of the user session fromthe LLC sublayer entity of the PC station to at least one peer LLCsublayer entity in the BSS; and assigning a VSID to the established VDS.20. The method of claim 15, wherein, when the method is performed by astation that is a non-PC station, the method further comprises: a)sending a management frame to the PC station of the BSS, the managementframe containing: 1) a special VSID, 2) a frame classifier, and 3) atleast one QoS parameter value that is associated with the new usersession; and b) indicating the management frame is for setting up thenew user session.